The present invention relates to the field of electrical connectors so-called of low force of insertion or of zero force of insertion, more particularly applicable to so-called flexible circuits.
To connect the layers of flexible layers, users require connectors with a minimum of insertion force or locking force, the latter being of the locking type in translation and requiring above all avoiding untimely disconnection.
There is known for example a zero insertion force connector described in U.S. Pat. No. 4,718,859, provided to receive a layer of cables.
Such a connector comprises two blocks:
a fixed block, generally connected to a support and provided for this purpose with blade contacts with a plug which are welded to the support, and
a movable block which coacts with the fixed block to immobilize the cables of the layer and ensuring contact between the cables of this layer and the blades, this requiring no insertion effort of the layer.
The movable block is mounted on the fixed block by translatory movement, guide means ensuring a suitable positioning of the two parts. The layer is then inserted between the two blocks. It then suffices to pivot the movable block relative to the fixed block to ensure pressing one portion of the blades against the cables, thereby ensuring the electrical connection. The locking is simultaneously ensured because any displacement in translation of the movable block relative to the fixed block is prevented.
The problem solved by this patent is that of the variations of thicknesses of the various layers to be inserted in this connector. Thus, these variations give rise to loss of pressure force of the plugs of the fixed block on the cables of the layer, unless different models are provided, each applicable to a type of layer. Given the very low sales price of these connectors, it would be of interest to provide a same connector permitting receiving different thicknesses of layers of cables.
To solve this problem, the base blades described in this document of the prior art have a particular C-shaped profile at offset ends thereby forming two offset contact points, above and below the layer, with a pressure abutment carried by the movable block which ensures an S-shaped deformation of the layer when it is thin, so as to place it in contact at two points.
When the layer is thick, the contact pressure is obtained in the same manner but the layer remains substantially flat.
The use of such a connector is carried out successively by emplacing the movable block on the fixed block, by introduction of the layer and then by rotation of the movable block relative to the fixed block, with the result of ensuring the pressurizing of the cables of the layer against the base blades with a plug, particularly when the layer is thin.
The present invention has for its object a connector to connect two layers of cables or a layer of cables and a bundle of cables whose elements have simple stripped shapes permitting simultaneous placing in contact and locking, low production cost whilst offering the desired functions and particularly reduced insertion force, reliability of contact, wiping at the point of contact during connection in one of the modifications, and an absence of transmission of vibrations in another of the modifications.
The application provides a connector whose two male and female portions are already mounted on the layers or bundles of cables.
To this end, the electrical connector with reduced insertion force according to the invention comprises a base provided with a blind recess provided to receive a plug, this base and this plug being each connected to a flexible circuit particularly of the type comprising a layer of electrical cables, and is characterized in that the blind recess receives the stripped ends of the cables of the flexible circuit and comprises means for guiding slidably upon introduction, more particularly in the form of a ramp guide means opening on a locking hole and the plug comprises electrical contacts secured to the cables of the associated circuit as well as translatory locking means, more particularly in the form of at least one fixed rib, of a suitable profile to assume a first orientation in which it can be displaced in translation in said ramp and a second orientation in which it is immobilized in the locking hole by swinging relative to the plug in the base.
More particularly, there is provided:
a blind recess in the base which comprises a plugging wall, a bearing wall facing it, two side walls for guidance and locking, each adapted to carry a ramp and a locking hole, the plugging wall making an angle a with the bearing wall, and
the plug comprises an upper surface and a lower surface from which the electrical contacts project, these two surfaces being substantially parallel and provided to coact with the plugging and bearing walls and two lateral surfaces, each adapted to carry a rib.
According to embodiments, the layer of cables of the base is disposed against the bearing wall of the blind recess and lower surface of the plug is facing this bearing wall, or vice versa.
According to an arrangement of the invention, the rib of the plug has a width equal to the width of the base ramp and its longitudinal axis is inclined relative to the plane of the lower and upper surfaces of the plug by an angle a, such that the base and the plug are aligned after locking.
The electrical contacts of the plug are either blade contacts, the head of each blade forming a cross resiliently bearing against the corresponding cable of the layer during swinging, or full blade contacts, the head of each blade coming into contact with the corresponding cable of the layer by wiping.
For production reasons, a preferred embodiment provides that the base comprises a support plate for the layer, of the attached type, this blade comprising means to retain the flexible circuit and securement means on said base.
More particularly, the plate comprises two lateral returns provided with securement means on the side walls of the base and holding and positioning pegs, provided to coact with holes provided in ears provided during manufacture of the flexible circuit.
This electrical connector comprises, according to an improvement, locking means upon swinging, provided with a ring slidably mounted on the upper end of the block of the plug and provided with two lateral profile positioning tongues adapted to penetrate each into the groove and corresponding ramp.